Re: [PATCH-1v4, expand] Enable vector mode for compare_by_pieces [PR111449]

[HAO CHEN GUI <guihaoc@linux.ibm.com>]

OK, I will take it.

Thanks
Gui Haochen

在 2023/10/24 16:49, Jiang, Haochen 写道:
> It seems that the mail got caught elsewhere and did not send into gcc-patches
> mailing thread. Resending that.
> 
> Thx,
> Haochen
> 
> -----Original Message-----
> From: Jiang, Haochen 
> Sent: Tuesday, October 24, 2023 4:43 PM
> To: HAO CHEN GUI <guihaoc@linux.ibm.com>; Richard Sandiford <richard.sandiford@arm.com>
> Cc: gcc-patches <gcc-patches@gcc.gnu.org>
> Subject: RE: [PATCH-1v4, expand] Enable vector mode for compare_by_pieces [PR111449]
> 
> Hi Haochen Gui,
> 
> It seems that the commit caused lots of test case fail on x86 platforms:
> 
> https://gcc.gnu.org/pipermail/gcc-regression/2023-October/078379.html
> https://gcc.gnu.org/pipermail/gcc-regression/2023-October/078380.html
> https://gcc.gnu.org/pipermail/gcc-regression/2023-October/078381.html
> https://gcc.gnu.org/pipermail/gcc-regression/2023-October/078382.html
> https://gcc.gnu.org/pipermail/gcc-regression/2023-October/078383.html
> https://gcc.gnu.org/pipermail/gcc-regression/2023-October/078384.html
> 
> Please help verify that if we need some testcase change or we get bug here.
> 
> A simple reproducer under build folder is:
> 
> make check RUNTESTFLAGS="i386.exp=g++.target/i386/pr80566-2.C --target_board='unix{-m64\ -march=cascadelake,-m32\ -march=cascadelake,-m32,-m64}'"
> 
> Thx,
> Haochen
> 
>> -----Original Message-----
>> From: HAO CHEN GUI <guihaoc@linux.ibm.com>
>> Sent: Monday, October 23, 2023 9:30 AM
>> To: Richard Sandiford <richard.sandiford@arm.com>
>> Cc: gcc-patches <gcc-patches@gcc.gnu.org>
>> Subject: Re: [PATCH-1v4, expand] Enable vector mode for 
>> compare_by_pieces [PR111449]
>>
>> Committed as r14-4835.
>>
>> https://gcc.gnu.org/g:f08ca5903c7a02b450b93143467f70b9fd8e0085
>>
>> Thanks
>> Gui Haochen
>>
>> 在 2023/10/20 16:49, Richard Sandiford 写道:
>>> HAO CHEN GUI <guihaoc@linux.ibm.com> writes:
>>>> Hi,
>>>>   Vector mode instructions are efficient for compare on some targets.
>>>> This patch enables vector mode for compare_by_pieces. Two help 
>>>> functions are added to check if vector mode is available for 
>>>> certain by pieces operations and if if optabs exists for the mode 
>>>> and certain by pieces operations. One member is added in class 
>>>> op_by_pieces_d to record the type of operations.
>>>>
>>>>   The test case is in the second patch which is rs6000 specific.
>>>>
>>>>   Compared to last version, the main change is to add a target hook 
>>>> check - scalar_mode_supported_p when retrieving the available 
>>>> scalar modes. The mode which is not supported for a target should be skipped.
>>>> (e.g. TImode on ppc). Also some function names and comments are 
>>>> refined according to reviewer's advice.
>>>>
>>>>   Bootstrapped and tested on x86 and powerpc64-linux BE and LE with 
>>>> no regressions.
>>>>
>>>> Thanks
>>>> Gui Haochen
>>>>
>>>> ChangeLog
>>>> Expand: Enable vector mode for by pieces compares
>>>>
>>>> Vector mode compare instructions are efficient for equality compare 
>>>> on rs6000. This patch refactors the codes of by pieces operation to 
>>>> enable vector mode for compare.
>>>>
>>>> gcc/
>>>> 	PR target/111449
>>>> 	* expr.cc (can_use_qi_vectors): New function to return true if
>>>> 	we know how to implement OP using vectors of bytes.
>>>> 	(qi_vector_mode_supported_p): New function to check if optabs
>>>> 	exists for the mode and certain by pieces operations.
>>>> 	(widest_fixed_size_mode_for_size): Replace the second argument
>>>> 	with the type of by pieces operations.  Call can_use_qi_vectors
>>>> 	and qi_vector_mode_supported_p to do the check.  Call
>>>> 	scalar_mode_supported_p to check if the scalar mode is supported.
>>>> 	(by_pieces_ninsns): Pass the type of by pieces operation to
>>>> 	widest_fixed_size_mode_for_size.
>>>> 	(class op_by_pieces_d): Remove m_qi_vector_mode.  Add m_op to
>>>> 	record the type of by pieces operations.
>>>> 	(op_by_pieces_d::op_by_pieces_d): Change last argument to the
>>>> 	type of by pieces operations, initialize m_op with it.  Pass
>>>> 	m_op to function widest_fixed_size_mode_for_size.
>>>> 	(op_by_pieces_d::get_usable_mode): Pass m_op to function
>>>> 	widest_fixed_size_mode_for_size.
>>>> 	(op_by_pieces_d::smallest_fixed_size_mode_for_size): Call
>>>> 	can_use_qi_vectors and qi_vector_mode_supported_p to do the
>>>> 	check.
>>>> 	(op_by_pieces_d::run): Pass m_op to function
>>>> 	widest_fixed_size_mode_for_size.
>>>> 	(move_by_pieces_d::move_by_pieces_d): Set m_op to
>> MOVE_BY_PIECES.
>>>> 	(store_by_pieces_d::store_by_pieces_d): Set m_op with the op.
>>>> 	(can_store_by_pieces): Pass the type of by pieces operations to
>>>> 	widest_fixed_size_mode_for_size.
>>>> 	(clear_by_pieces): Initialize class store_by_pieces_d with
>>>> 	CLEAR_BY_PIECES.
>>>> 	(compare_by_pieces_d::compare_by_pieces_d): Set m_op to
>>>> 	COMPARE_BY_PIECES.
>>>
>>> OK, thanks.  And thanks for your patience.
>>>
>>> Richard
>>>
>>>> patch.diff
>>>> diff --git a/gcc/expr.cc b/gcc/expr.cc index 
>>>> 2c9930ec674..ad5f9dd8ec2 100644
>>>> --- a/gcc/expr.cc
>>>> +++ b/gcc/expr.cc
>>>> @@ -988,18 +988,44 @@ alignment_for_piecewise_move (unsigned int
>> max_pieces, unsigned int align)
>>>>    return align;
>>>>  }
>>>>
>>>> -/* Return the widest QI vector, if QI_MODE is true, or integer mode
>>>> -   that is narrower than SIZE bytes.  */
>>>> +/* Return true if we know how to implement OP using vectors of 
>>>> +bytes.  */ static bool can_use_qi_vectors (by_pieces_operation op) 
>>>> +{
>>>> +  return (op == COMPARE_BY_PIECES
>>>> +	  || op == SET_BY_PIECES
>>>> +	  || op == CLEAR_BY_PIECES);
>>>> +}
>>>> +
>>>> +/* Return true if optabs exists for the mode and certain by pieces
>>>> +   operations.  */
>>>> +static bool
>>>> +qi_vector_mode_supported_p (fixed_size_mode mode,
>> by_pieces_operation op)
>>>> +{
>>>> +  if ((op == SET_BY_PIECES || op == CLEAR_BY_PIECES)
>>>> +      && optab_handler (vec_duplicate_optab, mode) !=
>> CODE_FOR_nothing)
>>>> +    return true;
>>>> +
>>>> +  if (op == COMPARE_BY_PIECES
>>>> +      && optab_handler (mov_optab, mode) != CODE_FOR_nothing
>>>> +      && can_compare_p (EQ, mode, ccp_jump))
>>>> +    return true;
>>>>
>>>> +  return false;
>>>> +}
>>>> +
>>>> +/* Return the widest mode that can be used to perform part of an
>>>> +   operation OP on SIZE bytes.  Try to use QI vector modes where
>>>> +   possible.  */
>>>>  static fixed_size_mode
>>>> -widest_fixed_size_mode_for_size (unsigned int size, bool 
>>>> qi_vector)
>>>> +widest_fixed_size_mode_for_size (unsigned int size, 
>>>> +by_pieces_operation
>> op)
>>>>  {
>>>>    fixed_size_mode result = NARROWEST_INT_MODE;
>>>>
>>>>    gcc_checking_assert (size > 1);
>>>>
>>>>    /* Use QI vector only if size is wider than a WORD.  */
>>>> -  if (qi_vector && size > UNITS_PER_WORD)
>>>> +  if (can_use_qi_vectors (op) && size > UNITS_PER_WORD)
>>>>      {
>>>>        machine_mode mode;
>>>>        fixed_size_mode candidate;
>>>> @@ -1009,8 +1035,7 @@ widest_fixed_size_mode_for_size (unsigned int
>> size, bool qi_vector)
>>>>  	  {
>>>>  	    if (GET_MODE_SIZE (candidate) >= size)
>>>>  	      break;
>>>> -	    if (optab_handler (vec_duplicate_optab, candidate)
>>>> -		!= CODE_FOR_nothing)
>>>> +	    if (qi_vector_mode_supported_p (candidate, op))
>>>>  	      result = candidate;
>>>>  	  }
>>>>
>>>> @@ -1019,9 +1044,14 @@ widest_fixed_size_mode_for_size (unsigned
>> int size, bool qi_vector)
>>>>      }
>>>>
>>>>    opt_scalar_int_mode tmode;
>>>> +  scalar_int_mode mode;
>>>>    FOR_EACH_MODE_IN_CLASS (tmode, MODE_INT)
>>>> -    if (GET_MODE_SIZE (tmode.require ()) < size)
>>>> -      result = tmode.require ();
>>>> +    {
>>>> +      mode = tmode.require ();
>>>> +      if (GET_MODE_SIZE (mode) < size
>>>> +	  && targetm.scalar_mode_supported_p (mode))
>>>> +      result = mode;
>>>> +    }
>>>>
>>>>    return result;
>>>>  }
>>>> @@ -1061,8 +1091,7 @@ by_pieces_ninsns (unsigned HOST_WIDE_INT l,
>> unsigned int align,
>>>>      {
>>>>        /* NB: Round up L and ALIGN to the widest integer mode for
>>>>  	 MAX_SIZE.  */
>>>> -      mode = widest_fixed_size_mode_for_size (max_size,
>>>> -					      op == SET_BY_PIECES);
>>>> +      mode = widest_fixed_size_mode_for_size (max_size, op);
>>>>        if (optab_handler (mov_optab, mode) != CODE_FOR_nothing)
>>>>  	{
>>>>  	  unsigned HOST_WIDE_INT up = ROUND_UP (l, GET_MODE_SIZE
>> (mode));
>>>> @@ -1076,8 +1105,7 @@ by_pieces_ninsns (unsigned HOST_WIDE_INT l,
>> unsigned int align,
>>>>
>>>>    while (max_size > 1 && l > 0)
>>>>      {
>>>> -      mode = widest_fixed_size_mode_for_size (max_size,
>>>> -					      op == SET_BY_PIECES);
>>>> +      mode = widest_fixed_size_mode_for_size (max_size, op);
>>>>        enum insn_code icode;
>>>>
>>>>        unsigned int modesize = GET_MODE_SIZE (mode); @@ -1317,8 
>>>> +1345,8 @@ class op_by_pieces_d
>>>>    bool m_push;
>>>>    /* True if targetm.overlap_op_by_pieces_p () returns true.  */
>>>>    bool m_overlap_op_by_pieces;
>>>> -  /* True if QI vector mode can be used.  */
>>>> -  bool m_qi_vector_mode;
>>>> +  /* The type of operation that we're performing.  */  
>>>> + by_pieces_operation m_op;
>>>>
>>>>    /* Virtual functions, overriden by derived classes for the specific
>>>>       operation.  */
>>>> @@ -1331,7 +1359,7 @@ class op_by_pieces_d
>>>>   public:
>>>>    op_by_pieces_d (unsigned int, rtx, bool, rtx, bool, by_pieces_constfn,
>>>>  		  void *, unsigned HOST_WIDE_INT, unsigned int, bool,
>>>> -		  bool = false);
>>>> +		  by_pieces_operation);
>>>>    void run ();
>>>>  };
>>>>
>>>> @@ -1349,11 +1377,11 @@ op_by_pieces_d::op_by_pieces_d (unsigned
>> int max_pieces, rtx to,
>>>>  				void *from_cfn_data,
>>>>  				unsigned HOST_WIDE_INT len,
>>>>  				unsigned int align, bool push,
>>>> -				bool qi_vector_mode)
>>>> +				by_pieces_operation op)
>>>>    : m_to (to, to_load, NULL, NULL),
>>>>      m_from (from, from_load, from_cfn, from_cfn_data),
>>>>      m_len (len), m_max_size (max_pieces + 1),
>>>> -    m_push (push), m_qi_vector_mode (qi_vector_mode)
>>>> +    m_push (push), m_op (op)
>>>>  {
>>>>    int toi = m_to.get_addr_inc ();
>>>>    int fromi = m_from.get_addr_inc (); @@ -1375,8 +1403,7 @@ 
>>>> op_by_pieces_d::op_by_pieces_d (unsigned int
>> max_pieces, rtx to,
>>>>      {
>>>>        /* Find the mode of the largest comparison.  */
>>>>        fixed_size_mode mode
>>>> -	= widest_fixed_size_mode_for_size (m_max_size,
>>>> -					   m_qi_vector_mode);
>>>> +	= widest_fixed_size_mode_for_size (m_max_size, m_op);
>>>>
>>>>        m_from.decide_autoinc (mode, m_reverse, len);
>>>>        m_to.decide_autoinc (mode, m_reverse, len); @@ -1401,7 
>>>> +1428,7 @@ op_by_pieces_d::get_usable_mode
>> (fixed_size_mode mode, unsigned int len)
>>>>        if (len >= size && prepare_mode (mode, m_align))
>>>>  	break;
>>>>        /* widest_fixed_size_mode_for_size checks SIZE > 1.  */
>>>> -      mode = widest_fixed_size_mode_for_size (size, m_qi_vector_mode);
>>>> +      mode = widest_fixed_size_mode_for_size (size, m_op);
>>>>      }
>>>>    while (1);
>>>>    return mode;
>>>> @@ -1414,7 +1441,7 @@ fixed_size_mode  
>>>> op_by_pieces_d::smallest_fixed_size_mode_for_size (unsigned int 
>>>> size)  {
>>>>    /* Use QI vector only for > size of WORD.  */
>>>> -  if (m_qi_vector_mode && size > UNITS_PER_WORD)
>>>> +  if (can_use_qi_vectors (m_op) && size > UNITS_PER_WORD)
>>>>      {
>>>>        machine_mode mode;
>>>>        fixed_size_mode candidate;
>>>> @@ -1427,8 +1454,7 @@
>> op_by_pieces_d::smallest_fixed_size_mode_for_size (unsigned int size)
>>>>  	      break;
>>>>
>>>>  	    if (GET_MODE_SIZE (candidate) >= size
>>>> -		&& (optab_handler (vec_duplicate_optab, candidate)
>>>> -		    != CODE_FOR_nothing))
>>>> +		&& qi_vector_mode_supported_p (candidate, m_op))
>>>>  	      return candidate;
>>>>  	  }
>>>>      }
>>>> @@ -1451,7 +1477,7 @@ op_by_pieces_d::run ()
>>>>
>>>>    /* widest_fixed_size_mode_for_size checks M_MAX_SIZE > 1.  */
>>>>    fixed_size_mode mode
>>>> -    = widest_fixed_size_mode_for_size (m_max_size, m_qi_vector_mode);
>>>> +    = widest_fixed_size_mode_for_size (m_max_size, m_op);
>>>>    mode = get_usable_mode (mode, length);
>>>>
>>>>    by_pieces_prev to_prev = { nullptr, mode }; @@ -1516,8 +1542,7 
>>>> @@ op_by_pieces_d::run ()
>>>>        else
>>>>  	{
>>>>  	  /* widest_fixed_size_mode_for_size checks SIZE > 1.  */
>>>> -	  mode = widest_fixed_size_mode_for_size (size,
>>>> -						  m_qi_vector_mode);
>>>> +	  mode = widest_fixed_size_mode_for_size (size, m_op);
>>>>  	  mode = get_usable_mode (mode, length);
>>>>  	}
>>>>      }
>>>> @@ -1543,7 +1568,7 @@ class move_by_pieces_d : public
>> op_by_pieces_d
>>>>    move_by_pieces_d (rtx to, rtx from, unsigned HOST_WIDE_INT len,
>>>>  		    unsigned int align)
>>>>      : op_by_pieces_d (MOVE_MAX_PIECES, to, false, from, true, NULL,
>>>> -		      NULL, len, align, PUSHG_P (to))
>>>> +		      NULL, len, align, PUSHG_P (to), MOVE_BY_PIECES)
>>>>    {
>>>>    }
>>>>    rtx finish_retmode (memop_ret);
>>>> @@ -1632,15 +1657,16 @@ move_by_pieces (rtx to, rtx from, unsigned
>> HOST_WIDE_INT len,
>>>>  class store_by_pieces_d : public op_by_pieces_d  {
>>>>    insn_gen_fn m_gen_fun;
>>>> +
>>>>    void generate (rtx, rtx, machine_mode) final override;
>>>>    bool prepare_mode (machine_mode, unsigned int) final override;
>>>>
>>>>   public:
>>>>    store_by_pieces_d (rtx to, by_pieces_constfn cfn, void *cfn_data,
>>>>  		     unsigned HOST_WIDE_INT len, unsigned int align,
>>>> -		     bool qi_vector_mode)
>>>> +		     by_pieces_operation op)
>>>>      : op_by_pieces_d (STORE_MAX_PIECES, to, false, NULL_RTX, true, cfn,
>>>> -		      cfn_data, len, align, false, qi_vector_mode)
>>>> +		      cfn_data, len, align, false, op)
>>>>    {
>>>>    }
>>>>    rtx finish_retmode (memop_ret);
>>>> @@ -1729,8 +1755,8 @@ can_store_by_pieces (unsigned
>> HOST_WIDE_INT len,
>>>>        max_size = STORE_MAX_PIECES + 1;
>>>>        while (max_size > 1 && l > 0)
>>>>  	{
>>>> -	  fixed_size_mode mode
>>>> -	    = widest_fixed_size_mode_for_size (max_size, memsetp);
>>>> +	  auto op = memsetp ? SET_BY_PIECES : STORE_BY_PIECES;
>>>> +	  auto mode = widest_fixed_size_mode_for_size (max_size, op);
>>>>
>>>>  	  icode = optab_handler (mov_optab, mode);
>>>>  	  if (icode != CODE_FOR_nothing
>>>> @@ -1793,7 +1819,7 @@ store_by_pieces (rtx to, unsigned
>> HOST_WIDE_INT len,
>>>>  		 optimize_insn_for_speed_p ()));
>>>>
>>>>    store_by_pieces_d data (to, constfun, constfundata, len, align,
>>>> -			  memsetp);
>>>> +			  memsetp ? SET_BY_PIECES : STORE_BY_PIECES);
>>>>    data.run ();
>>>>
>>>>    if (retmode != RETURN_BEGIN)
>>>> @@ -1814,7 +1840,7 @@ clear_by_pieces (rtx to, unsigned
>> HOST_WIDE_INT len, unsigned int align)
>>>>    /* Use builtin_memset_read_str to support vector mode broadcast.  */
>>>>    char c = 0;
>>>>    store_by_pieces_d data (to, builtin_memset_read_str, &c, len, align,
>>>> -			  true);
>>>> +			  CLEAR_BY_PIECES);
>>>>    data.run ();
>>>>  }
>>>>
>>>> @@ -1832,12 +1858,13 @@ class compare_by_pieces_d : public
>> op_by_pieces_d
>>>>    void generate (rtx, rtx, machine_mode) final override;
>>>>    bool prepare_mode (machine_mode, unsigned int) final override;
>>>>    void finish_mode (machine_mode) final override;
>>>> +
>>>>   public:
>>>>    compare_by_pieces_d (rtx op0, rtx op1, by_pieces_constfn op1_cfn,
>>>>  		       void *op1_cfn_data, HOST_WIDE_INT len, int align,
>>>>  		       rtx_code_label *fail_label)
>>>>      : op_by_pieces_d (COMPARE_MAX_PIECES, op0, true, op1, true,
>> op1_cfn,
>>>> -		      op1_cfn_data, len, align, false)
>>>> +		      op1_cfn_data, len, align, false, COMPARE_BY_PIECES)
>>>>    {
>>>>      m_fail_label = fail_label;
>>>>    }